On Fri, 16 Sep 2016 11:25:54 +0200
Christoph Lauber <christ...@midsommar.ch> wrote:
> Hi H
> Are you sure you really need the "Offset" field for your aims?
> Don't you need just the "Time frame size"? There you can choose "step
> width" like minutes, days, month, years...
> The offset should be a feature, you can time which style to display
> when. But I think this is not what you want to do.
Thanks for the response.
I will take two steps back and explain what I am trying to accomplish
rather than where I am having trouble.
I have been a professional C/C++ developer, but have never used Python.
(I could learn to write python scripts if required, but they are not
obvious to me - yet)
I have road crash data where, for each road crash, I have a field for
date and a different field for time. (The data came as csv, I put it
into postgis, but for Time Manager have saved it to a shp file)
The data is updated every couple of months, and starts in 2001.
When looking at road crash data I generally consider crashes in 5 year
groupings. I am wanting to use Time Manager to show the 5 year
(There are times I may want to change the length of the groupings, so I
want something where I can easily change from 5 years. I am currently
dealing only with calender years)
Using the 5 year groupings, this is I want from Time Manager:
Frame 1 - road crashes 2001 to 2005
Frame 2 - road crashes 2002 to 2006
Frame 3 - road crashes 2003 to 2007
Frame 12 - road crashes 2012 to 2016
My understanding is that for this the Time Frame Size is 'one year' as
that is the interval between each frame. (Correct me if I am wrong)
I have seen a number of sample files, and my intent was to create
5 copies of the data, and offset them to cover a 5 year period in each
To make the situation more challenging, I am also thinking of doing a
heatmap rather than just showing individual points. I do not think I
can create a heatmap using multiple layers.
My fall back solution is that I create a new table / layer that contains
the primary key from my crashes table, the coordinates of the crash and
a year in which to display it. Because each crash is being displayed in
5 different years, this table would have 5 entries for each crash,
but Time Manager would step through a heatmap for each
I was hoping I would not need to create a new table.
> > -----Ursprüngliche Nachricht-----
> > Von: h [mailto:hdi...@bigpond.net.au]
> > Gesendet: Dienstag, 13. September 2016 14:08
> > An: qgis-user <Qgisemail@example.com>
> > Betreff: [Qgis-user] "Time Manager" - Offset units
> > I have a couple of questions about the "Time Manager" plugin -
> > firstly Is this the right place for me to post them to?
> > This is the first of a couple of questions I have, so please
> > redirect me to the correct place if this is not it.
> > My first question is concerning the "Offset" field when adding
> > layers. I have a dataset I want to step through in years showing
> > data for current year and previous year.
> > I can do this, by setting the offset for the 'previous' year as
> > 32000000. I am guessing that the offset is in seconds (there are
> > about 32 million seconds in a year)
> > * Is my guess correct that the offset is in seconds?
> > * Can I change the unit of the offset (I would like to use years)?
> > * If the offset can only be entered in seconds, I will improve my
> > approximation of 32 million seconds, but what do I do about leap
> > years?
> > Many thanks,
> > H
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